1. The Field of the Invention
The present invention relates generally to the post-surgical treatment of closed wounds and specifically to methods and systems for concurrent aspiration and infusion of a wound site to manage pain, swelling, bleeding and infection.
2. The Relevant Technology
One of the most difficult aspects of enduring a major surgical procedure is coping with the post-operative pain and swelling. Commonly, opioid analgesics, sometimes referred to as narcotics, are administered post-operatively to counter the pain associated with wound healing and recovery. However, the use of systemic opioid analgesics, whether administered by oral, intramuscular, or intravenous methods, includes a host of possible undesirable side effects, including: respiratory depression, renal function depression, nausea, constipation, ataxia, confusion, sweating, and itching. The length of hospital stay for patients undergoing a major surgical procedure is, in part, determined by the need to monitor and control the side effects of systemically administered opioid analgesics.
More recently, infusion pumps have been used to percutaneously deliver local anesthetics directly to the surgical wound. Thus, many of the undesirable side effects of systemic opioid analgesics are avoided. Furthermore, medication dosage is considerably less than systemic delivery since the medication is delivered directly to the affected site. However, contemporary percutaneous pain medication infusion pumps do not provide consistent relief of pain.
Another challenge associated with percutaneous pain medication infusion pumps is the need to concurrently address edema, or fluid build-up and swelling, at the wound site. Aspiration of excess fluid has been attempted by the use of a separate and discrete percutaneous catheter connected to a vacuum source. However, concurrent use of a pain medication infusion pump and an aspiration catheter creates two significant compromises to the patient. First, two percutaneous catheters, one for the aspiration catheter and one for the infusion pump, potentially doubles the risk of infection since two percutaneous tracts are maintained. Second, an aspiration catheter coupled with an active vacuum source that is designed for the removal of fluid build-up tends to remove the infused pain medication before it has effectively produced the desired local anesthetic effect.